I have no problem with a protagonist of any sex, race, species, or whatever the hell a dev wants to do.
Dialogue is something that can negatively affect my experience with a game, unlike the aesthetic appearance of a character, though-- and I heard some pretty grating lines come out of the playable character in the gameplay reveal. The CG stuff was perfectly scripted and sounded nice as far as I'm concerned, but I can tell I'm going to despise the random little phrases pitched out over the course of play, and that usually only happens after dozens of hours in other games.
Might seem like an insignificant and petty thing to have a gripe about, but it's a concern to me nonetheless. I also have some reservations about the gameplay, but I won't judge that so early into this game's public existence.
Edit: I should acknowledge that I really disliked Delson from Second Son in all of the trailers and even more so when I bought the game at launch and began playing, but he grew on me the more I spent with the game (still don't really enjoy his comments or attitude, but I digress). That's perfectly possible with Horizon, too, once I begin to "know" the character-- it's only fair.